In 2002 the National Audit Office reported that levels of obesity in the UK had tripled over the previous 20 years. This makes the British among the fattest nations in Europe and, if nothing is done to halt the epidemic, it is feared that levels will soon reach those in the US where one person in every four is obese. Every year tens of thousands of people in the Western world are dying prematurely from heart disease, stroke and diabetes - all of them closely linked to obesity.